[plan] Introduce set-issue-field safe output (analogous to set-issue-type)

[github-actions]

Objective

Propose and implement a new set-issue-field safe output tool that provides granular control over individual issue fields, analogous to set-issue-type.

Context

The existing set-issue-type safe output provides a focused way to set a single field (type) on an issue. A similar set-issue-field tool would let workflows set a specific field by name and value without going through update-issue. Tracked in #30846.

Approach

1. Design the set-issue-field interface:
   • Parameters: issue_number, field_name, value (and optionally field_node_id to skip discovery)
2. Implement the tool in actions/setup/js/ following the pattern of set-issue-type
3. Register the tool in pkg/workflow/js/safe_outputs_tools.json
4. Add schema validation
5. Handle unknown field names and invalid values with actionable errors

Files to Modify

• actions/setup/js/ — add new set-issue-field handler
• pkg/workflow/js/safe_outputs_tools.json — register new tool
• schemas/ — JSON schema for new tool

Acceptance Criteria

• set-issue-field safe output accepts issue_number, field_name, and value
• Field is updated on the specified issue
• Unknown field names produce an actionable error suggesting discovery
• Unit tests cover success and error paths
• Documentation and schema reference updated
  Related to Implement Issue Fields Support in Safe Outputs #30846

Generated by Plan Command for issue #30846 · ● 3.1M · ◷

• expires on May 9, 2026, 6:53 PM UTC